Present day computer systems enable a user to create various types of documents. These documents can contain text, graphics, images or a combination of each. Many times the creator of a document for various reasons desires to keep secret the contents of a document. Often times the secrecy is for security reasons. In many businesses, various types of documents that exist on computer systems contain confidential information that can be related to the company's trade secrets and business strategies. Most technology related companies maintain much of their research and product development information on computer systems that are protected by elaborate security systems. Governmental agencies also maintain much of their documented information on a confidential basis. Even individuals keep important records and other information in confidential files.
Often, it is necessary to share documentation that contains confidential information with persons. Presently, there are various ways to secure the documents and prevent unauthorized persons from viewing the contents of a document. One way to protect documents is zip the document in a secured file that can be password protected. In this approach, when someone desires to access the document, that person must first submit the proper password. If the password is correct, the document is retrieved and displayed for the requesting viewer. During transmission of a document over a computing network such as the Internet, the document can be attached to an electronic message and transmitted with the message. The receiver of the message can download the attachment and with the proper password, retrieve the attached and secured document.
In other situations, a person must show that they have authority to access a computing network from which one can access certain confidential information. These systems typically exist in financial settings such as accessing bank or credit accounts.
A third technique used today to secure the contents of a document is to encrypt the document contents. In this approach, the document would be encrypted and stored by the document creator. To access the document, one would need to have the proper decryption key(s). In many cases, the documents would be transmitted over a computing network to a destination location. The encryption would serve to secure the document during the transmission of the document over the network. Again, at the destination location, decryption would occur using the appropriate decryption keys.
One disadvantage is that the current document security systems are all or nothing propositions. With reference to document encryption, today, the only known means of encrypting certain elements of a document is to encrypt the entire document. In some instances encryption currently may be accomplished only during a transmission (HTTPS). Regardless, the entire document is encrypted. The drawback to this approach is that encryption imposes a serious performance impact and usability impact. HTTPS transmissions, for example, are in the neighborhood of 20%-30% slower than decrypted HTTP transmissions. Similarly, encrypting an entire document locally is costly, especially when only certain parts of the document (for example, personal user name, telephone, address, and credit card numbers in an order) actually need the security that encryption provides. Furthermore, the process of encrypting the document is usually inconvenient, at best, requiring the user isolate it as a separate file and then invoking a suitable tool for encrypting it.
As mentioned, currently, document security is an all or nothing task. There remains a need for a document security system in which a user could select only specified portions of a document for concealment, while displaying other unconcealed portions of the document.